553 Can't open that file: No such file or directory

hello everyone, im new at the forum and a newbye in java,
not sure if this is the right section to post this...anyway...
im trying to upload files to my site via java using Apache common net 3.0.1 api
but cannot store file in my public directory cause i obtain "553 Can't open that file: No such file or directory"

permissions are write, read and execute, and in fact im able to delete via java from public directory all the files i want to,
but cannot store new ones

here's the code:

here's the output :

LOG true
230 OK. Current restricted directory is /

----- list of file i have in my public directory------

FILE true
STORED false
553 Can't open that file: No such file or directory

took a look on the net but didnt found any help
can someone more skilled than me tell me where am i wrong??

Variables should start with a lowercase letter.
The variable port is declared as a String however later in the code it is parsed to an int. Why not declare it as an int?
The String variables are declared within brackets. This is unnecessary and I would remove them.
You should declare and initialize variables just before you need them. The variable fis is declared 13 lines before it is used.
Closing fis & disconnecting with the client should happen in a finally block. Otherwise in case an exception occurs the resources will not be closed.